This highlights the similarities between human sensors and their engineering counterparts. Taking this approach enables to view the human body as a system, that is, from the perspective of an engineer. Humans have recreated most human sensors in robots – eyes, ears and sensors for temperature, touch and smell. It can be categorized as

SensorReceptorsStimuli

A real or imaginary machine that is controlled by a computer and is often made to look like a human or animal A machine that can do the work of a person and that works automatically or is controlled by a computer

Currently, there is no concrete definition of what constitutes a sense, but in general, a sense is a means of perception that is detected by a specific sensory organ; for example, the eye is the organ that allows one to see and the ear allows one to hear. Sometimes senses are perceived concurrently with each other; for example, most people see and hear the person with whom they are speaking. It is quite common for people to learn about the world by touching, tasting, smelling, seeing, and hearing things around them; in this way, senses are the means of understanding new concepts and gaining knowledge. In some cases, a person may not be able to use one or more human sense, for example, when a person is blind or deaf. Usually, in such a case, a different sense will be heightened to make up for the lacking one; so if a person cannot see, he may be able to hear extremely wellThere are between five and 21 human senses, but it is generally agreed that five is the minimum. The basic five senses are touch, taste, smell, sight, and hearing. Some people choose to include an additional four senses to the list, which include the sense of temperature, pain, balance, and body position.The nervous system determines the countless we feel all over our bodies every day. How does this work? What causes your leg to feel tingly when it falls asleep? How do you know when you're about to sneeze?

In cell biology, a structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance. There are many receptors. There is a receptor for (insulin); there is a receptor for low-density lipoproteins  (LDL); etc. The receptor for substance P, a molecule that acts as a messenger for the sensation of pain, is a unique harbor on the cell surface where substance P docks. Without this receptor, substance P cannot dock and cannot deliver its message of pain. Variant forms of nuclear hormone receptors mediate processes such as cholesterol metabolism and fatty acid production. Some hormone receptors are implicated in diseases such as diabetes and certain types of cancer. A receptor called PXR appears to jump-start the body's response to unfamiliar chemicals and may be involved in drug-drug interactions.In neurology, a terminal of a sensory nerve that receives and responds to stimuli.

Sensory systems code for four aspects of a stimulus; type (modality), intensity, location, and duration. Arrival time of a sound pulse and phase differences of continuous sound are used for localization of sound sources. Certain receptors are sensitive to certain types of stimuli (for example, different mechanoreceptors respond best to different kinds of touch stimuli, like sharp or blunt objects). Receptors send impulses in certain patterns to send information about the intensity of a stimulus (for example, how loud a sound is). The location of the receptor that is stimulated gives the brain information about the location of the stimulus (for example, stimulating a mechanoreceptor in a finger will send information to the brain about that finger). The duration of the stimulus (how long it lasts) is conveyed by firing patterns of receptors. These impulses are transmitted to the brain through afferent neurons.

 It is an event that evokes a specific functional reaction in an organ or tissue. It is areas of the brain which respond to auditory stimuli. it arouses activity or energy in someone or something; a spur or incentive.

•Some people experience something called synesthesia where they may perceive some sound and think of it as a color. So a dog barking may be “red” to them or the like. This condition does not generally occur naturally, though it can; it usually manifests itself when people are under the influence of hallucinogens.

•Cattle tend to align themselves north-south, which leads some researchers to believe they have a strong magnetoception sense.

•Sharks, stringrays, and chimeara all possess an electroreceptive organ called an ampullae of Lorenzini. This organ gives them the ability to detect even small variations in electric potential. They can use this to detect magnetic fields, among other things.

There are some people who do seem to have other senses. For example, there are many people who can sense impending weather changes. I could always sense when I was about to make a mess (the sense also known as "eyes in the back of the head"). And many people feel that they can sense when someone else is looking at them. No scientific proof for any of these senses, yet...

Other animals also have receptors to sense the world around them, with degrees of capability varying greatly between species. Humans have a comparatively weak sense of smell relative to many other mammals while some animals may lack one or more of the traditional five senses. Some animals may also intake and interpret sensory stimuli in very different ways. Some species of animals are able to sense the world in a way that humans cannot, with some species able to sense electrical and magnetic fields, and detect water pressure and currents.

One such method for testing whether humans have magnetoception is by placing a strong magnetic field near a person and then disorienting them. Results have shown that people in this scenario perform significantly worse at being able to re-orient themselves in terms of the cardinal points than people who are not near a strong magnetic field. More conclusive evidence has been demonstrated by examining subject’s brains when magnetic fields are produced near a person. It has been shown that these magnetic fields will evoke a response in the brain’s activity.

In eyes, two different types of light sensors. One set of sensors, called the rods, senses light intensity and works well in low-light situations. The other type, called cones, can sense color

It is the sense of sound perception. Hearing is all about vibration. Mechanoreceptors turn motion into electrical nerve pulses, which are located in the inner ear. Since sound is vibration, propagating through a medium such as air, the detection of these vibrations, that is the sense of the hearing, is a mechanical sense because these vibrations are mechanically conducted from the eardrum through a series of tiny bones to hair-like fibers in the inner ear, which detect mechanical motion of the fibers within a range of about 20 to 20,000 hertz.

In your skin, there are at least five different types of nerve endings: heat sensitivecold sensitivepain sensitiveItch sensitive

pressure sensitiveThis has been found to be distinct from pressure, temperature, pain, and even itch sensors.

On the tongue, there are chemical receptors that give us our sense of taste. (sweet, salty, sour, bitter, and umami)

In your nose, there are chemical sensors that give you your sense of smell.

Ability to sense heat and cold. This is thought of as more than one sense. This is not just because of the two hot/cold receptors, but also because there is a completely different type of thermoceptor, in terms of the mechanism for detection, in the brain. These thermoceptors in the brain are used for monitoring internal body temperature.

This was once thought to simply be the result of overloading other senses, such as “touch”, but this has been found not to be the case and instead, it is its own unique sensory system. There are three distinct types of pain receptors: cutaneous (skin), somatic (bones and joints), and visceral (body organs).

The sense that allows to keep balance and sense body movement in terms of acceleration and directional changes. This sense also allows for perceiving gravity. The sensory system for this is found in your inner ears and is called the vestibular labyrinthine system. Anyone who’s ever had this sense go out on them on occasion knows how important this is. When it’s not working or malfunctioning, you literally can’t tell up from down and moving from one location to another without aid is nearly impossible. Also in ears are sensors that detect orientation in the gravitational field -- they give sense of balance.

This sense gives the ability to tell where body parts are, relative to other body parts. This sense is one of the things police officers test when they pull over someone who they think is driving drunk. The “close your eyes and touch your nose” test is testing this sense. This sense is used all the time in little ways, such as when you scratch an itch on your foot, but never once look at your foot to see where your hand is relative to your foot.

Surprisingly, this is a distinct sensor system from other touch-related senses.

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In muscle and joints, there are sensors that tell the different parts of body are and about the motion and tension of the muscles. These senses let us, for example, touch our index fingers together with our eyes shut.Tension Sensors: These are found in such places as your muscles and allow the brain the ability to monitor muscle tension

These are found in such places as the lungs, bladder, stomach, and the gastrointestinal tract.  A type of stretch receptor, that senses dilation of blood vessels, is also often involved in headaches. In your bladder, there are sensors that indicate when it is time to urinate. Similarly, your large intestine has sensors that indicate when it is full.

Conductive Rubber Cord Stretch Sensor

These trigger an area of the medulla in the brain that is involved in detecting blood born hormones and drugs. It also is involved in the vomiting reflex.

Scientists have been studying the neurological mechanisms of thirst for decades. Early on, they discovered that the body’s primary “thirst center” in the brain is the hypothalamus, a deep structure that also regulates body temperature, sleep, and appetite. Special sensors in the hypothalamus are constantly monitoring the blood’s concentration of sodium and other substances. The hypothalamus also receives inputs from sensors in the blood vessels that monitor blood volume and pressure. When blood volume or pressure falls too low—from bleeding, for example, or from the excessive loss of fluid in sweat or diarrhea, or when blood sodium concentration rises too high from eating salty snacks, or as the result of certain diseases, the hypothalamus sends out a strong message: Drink something. Now.

This system allows your body to detect when you need to eat something. The hypothalamus senses external stimuli mainly through a number of hormones such as leptin, ghrelin, PYY 3-36, orexinand cholecystokinin; all modify the hypothalamic response. They are produced by the digestive tract and by adipose tissue (leptin). Systemic mediators, such as tumor necrosis factor-alpha (TNFα), interleukins 1 and 6 and corticotropin-relasing harmone (CRH) influence appetite negatively;

This is the ability to detect magnetic fields, which is useful in providing a sense of direction when detecting the Earth’s magnetic field. Unlike most birds, humans do not have a strong magentoception, however, experiments have demonstrated that we do tend to have some sense of magnetic fields. The mechanism for this is not completely understood; it is theorized that this has something to do with deposits of ferric iron in our noses. This would make sense if that is correct as humans who are given magnetic implants have been shown to have a much stronger magnetoception than humans without.

There exists a type of bacteria, called magnetotactic bacteria, that build magnets inside themselves in order to orient themselves with the Earth’s magnetic field. They also migrate and form chains of themselves along magnetic field lines.

This one is debated as no singular mechanism has been found that allows people to perceive time. However, experimental data has conclusively shown humans have a startling accurate sense of time, particularly when younger. The mechanism we use for this seems to be a distributed system involving the cerebral cortex, cerebellum, and basal ganglia. Long term time keeping seems to be monitored by the suprachiasmatic nuclei (responsible for the circadian rhythm). Short term time keeping is handled by other cell systems.

Intuition is also sometimes included as a sense Intuition, a phenomenon of themind, describes the ability to acquire knowledge without inference or the use of reason

People with Parkinson’s disease and ADD have severely impaired sense of time passage compared to “normal” people.

A sensory receptor which receives stimuli from within the body, especially one that responds to position and movement.(sense of relative position of body parts) comes from the Latin “proprius”, meaning “one’s own”.

More recently, it has been shown that certain birds have the ability to see magnetic fields.  How this works is the Earth’s magnetic field effects how long a certain molecule, cryptochrome, in their photoreceptor cells stays in the active state.  This then affects the light sensitivity of the bird’s retinal neurons. The net effect is the birds can perceive magnetic fields with their eyes.   The biological magnate and ability to perceive magnetic fields with their eyes are thought to combine to form a very accurate mapping and directional system in the birds.

  It is the Pressure exerted by circulating blood upon the walls of blood vessels. When used without further specification, "blood pressure" usually refers to the arterial pressure in the systemic circulation. It is usually measured at a person's upper arm. Blood pressure is usually expressed in terms of the systolic (maximum) pressure over diastolic (minimum) pressure and is measured in millimeters of mercury (mm Hg). It is one of the vital signs along with respiratory rate, heart rate, oxygen saturation, and body temperature. Normal resting blood pressure in an adult is approximately 120/80 mm Hg.

It is the speed of the heart beat measured by the number of contractions of the heart per unit oftime — typically beats per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excrete carbon dioxide. Activities that can provoke change include physical exercise, sleep, anxirty, stress, illness, ingesting, and drugs

Hair is a protein filament that grows from follicles found in the dermis, or skin. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fine vellums hair. Most common interest in hair is focused on hair growth, hair types and hair care, but hair is also an important biomaterial primarily composed of protein, notably keratin. It is often used to indicate a person's personal beliefs or social position, such as their age, gender, or religion

The opening and cavity in the lower part of the human face, surrounded by the lips, through which food is taken in and vocal sounds are emitted. An opening or entrance to a hollow, concave, or enclosed structure.

 

Psychophysics

Discriminatory (epicritic) and

Emotional (protopathic) Hedonic (pleasure-pain) Vomeronasal organSensing gravitElectro locationEcholocationElectroreceptionCurrent detectionPolarized light direction/detectionSlit sensillae of spiders